“They have vision problems, orthopedic problems, heart problems,” said Nancy Burke about their three daughters.

The love and support they experience everyday doesn’t stop either.

“(Our daughters) get up every single day with a smile on their face, even though each day is so challenging for them, how can we not get up with a smile on our faces,” said Nancy Burke. “How can we not just enjoy every moment that we have?”

It all started when the oldest of their three girls, Jillian, started having trouble in school at 6 years old.

“Everything was absolutely fine prior to that. She met all of her milestones along the way. We really had no health issues,” said Nancy Burke.

But Jillian's health kept getting worse, and it would be another three years before the Burkes were finally told why.

Jillian had Sanfilippo Syndrome Type C, the rarest form of an already rare, genetic disease that destroys a person's central nervous system. Researchers estimate just 100 people worldwide have Type C, and the Burkes soon found out daughters, Lindsay and Kelsey, did too.

“This is really one of the most terrible diseases that exist,” said Dr. Gerry Berry, director of the Metabolism Program at Boston Children’s Hospital. “Material accumulates in the body in the brain, unfortunately … but it also causes some other abnormalities, such as coarse facial features and sometimes bone disease.”

With no cure and no treatments, the Burkes were told all they could do was take the girls home and love them.

“At that time, they told us the average life expectancy was 14,” said Nancy Burke. “You're so shocked, and your heart is, like, ripped out of you that you just go numb … But then, you can’t give into it or wallow in it because you have a family to take care of.”

Over the years, the Burkes have had to watch the children they once knew slip away.

“They played basketball, soccer. They rode horses … They did everything. They were just regular kids,” said Paul Burke.

“We got to know them. We got to know the people that we thought that they were going to be,” said Nancy Burke.

Jillian was their happy, little sunshine. Lindsay was sweet and curious. Kelsey was known as the spitfire of the family.

Fast forward to today, and all three have cognitive impairments, trouble communicating, and balance issues. Lindsay has a feeding tube. But despite it all, their sweet spirit and strength still shine through. All three girls, now in their 20s, are beating the odds.

“We still believe that something can be done,” said Nancy Burke. “That they can have a future, that things can be reversed.”

“I don’t know if it’s too late for them, but maybe some other parent wouldn’t have to go through this," said Paul Burke.

Sanfilippo is an orphan disease, meaning there aren't any pharmaceutical companies working on treatments, and neither is the government. So the Burkes are pounding the pavement themselves, working hard to raise awareness and money for research that could save their girls' lives.